Series multiple electric controller



(No Mbdell) 3 Sheets-Sheet 1.

A. P. KNIGHT. SERIES MULTIPLE ELECTRIC GONTEOLLEE. No. 507,547. PatentedOct. 31, 1893.

WITNESSES: LINVENTOR: Mum PJ'CVQW ATTYS (No Model.) 3 Sheets-Sheet 2.

A. P. KNIGHT. SERIES MULTIPLE ELECTRIC CONTROLLER. No. 507,547. PatentedOCt. 31,1893.

WITNESSES:

(No Model.) 3 Sheets-Sheet 3.

A. P. KNIGHT.

SERIES MULTIPLE ELECTRIC CONTROLLER.

' UNITED STATES PATENT OFFICE.

ARTHUR P. KNIGHT, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

SERIES MULTIPLE ELECTRIC CONTROLLER.

SPECIFICATION forming part of Letters Patent No. 507,547, dated October31, 1893.

I Application filed January 26,1892. Serial No. 419,268- (No model.)

To all whom it may concern.-

Be it known that I, ARTHUR P. KNIGHT, a citizen of the United States,residing at Boston, county of Suffolk, State of Massachusetts, haveinventeda certain new and useful Improvement in Series Multiple ElectricControllers, of which the following is a specification. I

This invention relates to means for con-trolling electric motors, andfor transferring-such apparatus from series to multiple relation,orvice' versa, without at any time wholly breaking the circuit ofeither-of such motors. For this purpose supposing the devices to be inseries, a connection is made around each of them, from their lineterminals to theirjunction terminals, such connection including aresistance sufficient to prevent short-circuiting of either the devicesor the line itself.

This resistance is in fact preferably such that under the normalconditions of use at the time of transfer, each resistance branch willtake about the same current that passes through each of the electricdevices. This being the case, the junction between the motors will carrylittle or no current and may then be severed without materially changingthe circuitccnditions, and therefore without great sparking.

My invention is designed particularly for use on constant potentialcircuits, and more especially for transferring a pair of electric motorsconnected to such circuit, from series to multiple relation, or Viceversa. It is applicable for instance to the case of an electric railwaycar driven by two motors, which are thus connected to a common load, itbeing desirable to change the relation of such motors as aforesaid, toeffect the changes in speed.

In the accompanying drawings Figure 1 is aplan view of a switch andcircuit connections adapted to carry out my invention. Fig. 2 is avertical section of the switch. Figs. 3, 4, 5, 6, and 7 show successivepositions ofthe switch after it has left the open position of Fig. 1.Fig. 10 shows in diagram the electrical con nections for the severalpositions of the switch.

L, L may represent constant potential lines; or connections to aconstant potential tute in effect movable line terminals. contacts 1*, rr are connected together and Figs. 8 and 9 showmodifications,-andswitches for similar purposes are now common in theart and are made up in many different .designs, such as the cylinderform,

the disk form and the lever form. Any one of these forms may be adoptedas found most convenient. I have shown the lever type ofswitch,tofacilitateexplanation. Itcomprises a handle or actuator H, across arm C and two insulated terminals t, t, all connected mechanicallytogether, as by being mounted on a disk or carrier 0 pivoted at 0. Theopposite ends of cross arm 0 traverse respectively the two series ofcontacts r,r ,r r ,r r located respectively adjacent to contacts 0, c.The terminals 25, t traverse said series of contacts, and contacts 0,0,and simultaneously bear upon the segments Z, Z which being connected tothe line terminals of the motors M, M, cause the pieces t, t to consti-The to contact 0 by resistances R. Similar connections to resistance Rare made between contacts 4", r r, and c.

Fig. 1 represents the switch as in the open position, the cross arm Cbeing slightly behind the first contacts r, r, and the arms 2 ,15 beingstill further behind,and, preferably out of contact also with the linesegments-l, Z. The circuit of both the motors is now open. On turningthe switch to position of Fig. 3, the motors are placed in series witheach other and with all of the resistances, the circuit being asfollows: line L, motor M, contact 0, resistances R, contact 4, cross armC, contact r resistances R, contact 0, motor M, line L. The resistanceso introduced has the beneficial effect of preventing undue rush ofcurrent to the motors in starting, and more or less of it may be leftin, to give a very slow speed, or the switch may be turned to positionofFig. 4, where all of the resistances are It is ob-- cut-out, the motorsbeing directly in series through the cross bar. In this position arms25, t are near, but not in contact with the initial contacts 0", 7. Nowto transfer the motors from series to multiple connection, the switch isfurther turned, and passing into position of Fig. 5, brings arms ormovable line terminals 15, t on to contacts 1", 1, before contact isbroken between cross arm U and contacts a, 0. Two circuits can then betraced, one as before, through the motors and cross arm, another fromline L to connection 1, line segment Z, arm 2?, contact 4", resistancesR, contact 0, cross arm 0, segment Z, connection 2 and out to line L.The current in the first circuit is determined by the electromotiveforce of the line, the resistance of the motors and thecounter-electromotive force of the motors. The current in the secondcircuit is determined by the line potential and the resistances.Assuming a that the transfer will generally be made under certainconditions of motor-speed, t. 6., at

about a'certain cou nter-electromotive force, it

is apparent that the resistances R, B may be so proportioned that thecurrents flowing in I the two circuits above traced shall be aboutequal. the current pass through the cross arm 0 in opposite directions,so that with the aforesaid substantial equality there would be little orno current passing through said cross arm, each motor in fact beingsupplied with current only through the rheostat R or R connected to theother side of the circuit. Un-- the motors are in multiple with aresistance in series with each, and byfurther movement of the switchthis resistance, or so much of it as desired, may be cut-out, the switchcoming finally to position of Fig. 7, with the motors in simple multipleconnection.

In Fig. 10 therespective diagrams a, 19,0, (Z, c, show the circuitsunder the several conditions above described. In diagram athetwo motorsare in series with the two resistances, in diagram bthey are in serieswithout resistance, in diagram 0 each motor-is shunted through theresistance, in diagram 01 the immediate connection between the motors issevered, and each motor is inseries with a resistance, but in multiplewith respect to the other motor, while in diagram 6 the two motors :arein multiple without resistance.

Independently of the exact or even approximate neutralization of thecurrent in the But the said two circuits or-paths for cross arm, orjunction, it will be seen that this controller has the advantage ofalways leaving a path for the field magnet discharge, so that if thecurrent through the motor is weakened, the energy of extra currentdischarging from the field magnets is taken up in a closed circuit.

Of course in applying this invention to electric railway service, itwould be used in conjunction with any usual or suitable de vices tosupplement its action, for example, reversing contacts or switches forthe motor armatures or loop connections for the fields. Thus in Fig. 8are shown resistances R R shunting the field magnets and connected toextra or final contacts 8, s, so that when arm 0 or arms t, t bridge thecontacts 0 s, 0' 8 11119 motor field magnets are partially shunted,giving a well known accelerating effect.

In Fig. 9 extra resistances R R are connected between contacts 0 s and cs,so that they are introduced into the cross connection before breakingthe same, and the liability of a heavy current being broken is stillfurther diminished. This extra resistance intro duced before breakingmay be of any usual or suitable magnitude, and may of course beintroduced in sections. Similarly the two series of resistances 7'', r&c., may be divided up into anydesirable number, or each series mayconstitute only one resistance. In that case, with the form shown inFig. 1, only contacts c, c, and contacts r, 0"", would be necessary, asingle resistance R connecting c and r and another resistance Rconnecting c and r, the contacts being, however, in any case so placedthat the switch arms do not break in passing from one to the other.

In case it is desired to regulate the mechanical action of the switch,so as to prevent its too rapid manipulation, or to cause it to come torest with certainty in certain normal stopping and running positions,suitable clevices for these purposes may be employed. Thus in Fig. l areindicated in dotted lines, a ratchet wheelw and spring pawlw', whichengage in obvious manner to prevent dangerously rapid rotation of theswitch, and also to hold it in to certain definite positions, such asthe open position, a series resistance position, the full seriesposition, and the full multiple position. This snapping action of j theswitch can be facilitated by the interposition of a lost motionconnection between the actuator I1 and the switch proper. It will alsobe understood that a single switch may be actuated in auysuitab'lemanner from'controlling hand levers at each end of the car, and may beplaced in any suitable location on the car, or duplicate switches may bepro vided at opposite ends of the car. In any case the switch may beprovided with duplicate cross connected setsof contacts and reversingcontacts in order to reverse the connections of the armature in wellknown manner. It is obvious also that the motors when open circuitedmaybe altogether disconnected from the lines, the circuit being closedto each motor only as the switch comes to the position indicated in Fig.3. Thus when the motors are stated to be connected to the lines, it doesnot mean that such connections are permanent, but that they exist duringthe process of changing the connections of the motors in accordance withthis invention.

I am aware that it has been heretofore proposed to change motors on aconstant potential circuit from series to multiple relation for thepurpose of regulating the power and speed of the mechanism driven bysuch motors in common, but the devices originally suggested foreffecting such a change in the relations of the motors contained noprovision for overcoming the difficulty presented by the destructive arewhich is produced by the rupture of the circuit ata time when betweendifferent parts of such circuit there existed a difierence in electromotive force arising either from the impressed electro-motive force ofthe line, the counter-electro-motive force or the self-induction of themotor. Subseq-uent inventors have, it is true, attempted to deviseswitching apparatus for effecting a change of the motors from series tomultiple relation which would be free from objection on account of theaforesaid difficulty. One plan for securing the desired resultscontemplates the insertion of a sufficient resistance to reduce the linecurrent to a minimum at the moment of making a change in theconnections, but such an arrangement introduces the further diflicultythat the driven mechanism must be momentarily deprived of its motivepower at each change, while the constant, use of a resistance is bothwasteful of energy and causes excessive wear on the resistance contacts.It has also been proposed in a constant potential system to change anelectric motor from series to multiple relation with a second motor, byfirst reducing its field magnet strength until it is practically dead;then establishing a connection around it, and finally disconnecting themotor from its series relation and changing it to a multiple relationwith the other motor. In such an arrangement however, it has been foundimpossible to satisfactorily discharge the field magnetism, and apartfrom this difficulty it is to be also observed that when the shunting orshort-circuiting connection is established the machine is in effect nota motor at all, but simply an inactive coil because it .has beendeprived of the power to exercise the functions of a motor. I,therefore, for the purpose of distinguishing my invention from such amethod desire it to be understood that wherever in the foregoingspecification and, in the following claims I have stated that a.

Over the method mentioned above and over all others heretofore devisedfor the purpose of effecting the change of electric motors from seriesto multiple relation, I consider that the essential feature of myimprovement resides in the fact that a connection is established arounda motor from its line terminal to its junction terminal, while it isstill active and prior to the severance of the series circuit thatextends through the motors from one line to the other. After thisconnection has been established, the motor is in such condition that itis a simple matter to disconnect the shunted motor from its seriesrelation with the other motor by any suitable switch, so that it may beincluded in a separate independent circuit, passing directly fromoneline to the other either with or without a resistance includedtherein. By treating both motors in the same manner and suitablyadjusting the resistance of the shunting circuits I I am enabled toeffect without difficulty the desired change in the relation of themotors from series to multiple.

WVhat I claim as new, and desire to secure by Letters Patent, is

1. The combination with a constant potential circuit of an electricmotor in series with a second motor on the said circuit, a separableconnection for said motor, and a connection around it containing aresistance.

2. The improvement in the method of changing an electric motor fromseries to multiple relation with a second motor by interrupting theseries circuit and establishing multiple circuits which consists inmaking a connection around the motor from its line terminal to itsjunction terminal prior to the interruption of the series circuit.

. 3. The improvement in the method of changing an electric motor fromseries to multiple relation with a second motor by interrupting theseries circuit and establishing multiple circuits, which consists inmaking a connection containing a resistance around the motor from itsline terminal to its j unction terminal prior to the interruption of theseries circuit.

4. The improvement in the method of series multiple control involvingthe changing of an electric motor from series to multiple relation witha second motor by interrupting the series circuit and establishingmultiple circuits, which consists in inserting a resistance in theseries circuit and then making a connection containing the saidresistance around the motor from its line terminal to its junctionterminal prior to the interruption of the series circuit.

5. The improvement in the method of series multiple control involvingthe changing of an electric motor from series to multiple relation witha second motor by interrupting the series circuit and establishingmultiple circuits, which consists in placing a resistance in the seriescircuit,-removing said resistance, and

making a connection including the said re- ICO IIO

sistance around the motor from its line terminal to its junctionterminal prior to the interruption of the series circuit.

6. Theimprovementin the methodof series multiple control involving thechanging of an electric motor from series to multiple relation with asecond motor by interrupting the series circuit and establishingmultiple circuits, which consists in placing a resistance in the seriescircuit, gradually removing said resistance,.and making a connectionaround the motor from its line terminal to its junction terminal priorto the interruption of the series circuit.

7. Theimprovement in the method of series multiple control involving thechanging of an electric motor from series to multiple relation with asecond motor by interrupting the series circuit and establishingmultiple circuits, which consists in placing a resistance in the seriescircuit, gradually removing said resistance, and making a connectionincluding the said resistance around the motor from its line terminal toits junction terminal prior to the interruption of the series circuit.

8. Theimprovement in the method of series multiple control involving thechanging of an electric motor from series to multiple relation with asecond motor by interrupting the series circuit and establishingmultiple circuits, which consists in placing a resistance in the seriescircuit, removing the said resistance, making a connection including thesaid resistance around the motor from its line terminal to its junctionterminal, changing the connections from series to multiple with the saidresistance in series with one of the motors, and finally removing theresistance.

9. Theimprovementin the method of series multiple control of twoelectric motors which consists in regulating the motors while in series,then changing one from series to multiple relation with the other byfirst making a connection around it from its line terminal to itsjunction terminal, and then changing the connections and finallyregulating the two in multiple.

10. Theimprovement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in series,then changing one from series to multiple relation with the other byfirst making a connection including a resistance around it from its lineterminal to itsjunction terminal, and then changing the connections andfinally regulating the two in multiple.

11. The improvement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in seriesby means of resistance, then changing one from series to multiplerelation with the other by first making a connection around it from itsline terminal to its junction terminal, and then changing theconnections and finally regulating the two in multiple.

12. The improvement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in seriesby means of resistance, then changing one from series to multiplerelation with the other by first making a connection around it from itsline terminal to its junction terminal, and then changing theconnections and finally regulating the two in multiple by means ofresistance.

13. The improvement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in seriesby means of resistance, then changing one from series to multiplerelation with the other by first making a connection including the sameresistance around it from its line terminal to it-sjunction terminal,and then changing the connections and finally regulating the two inmultiple.

14. The improvement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in seriesby means of resistance, then changing one from series to multiplerelation with the other by first making a connection around it from itsline terminal to its junction terminal, and then changing theconnections and finally regulating the two in multiple by means of thesame resistance aforesaid.

15. The improvement in the method of series multiple control of twoelectric motors which consists in regulating the motors while in series,then changing one from series to multiple relation with the other byfirst making a connection including the same resistance around it fromits line terminal to its junction terminal, and then changing theconnections and finally regulating the two in multiple by means of thesaid resistance.

16. The improvement in the method of series multiple control of twoelectric motors which consists in changing them from series to multiplerelation by first making a connection around each of the two motors fromits line terminal to itsjunction terminal, and then changing theconnections from series to multiple.

17. The improvement in the method of series multiple control of twoelectric motors which consists in changing them from series to multiplerelation by first making a connection including a resistance around eachof the two motors from its line terminal to its junction terminal, andthen changing the connections from series to multiple.

18. The method of controlling electric motors and changing them fromseries to multiple, which consists in establishing a circuit includingtwo motors, and two resistances all in series, then cutting out saidresistances, thus making a direct series connection between the motors,then making a connection around each motor, including one of saidresistances, then breaking said direct series connection and thencutting out the resistances from the resulting multiple connections.

19. The combination with two electric motors, of two resistances,connections including said motors and resistances, all in series,connections including said motors directly in series independently ofthe resistances, connections including each resistance in series withone of the motors and in multiple with the other motor, and circuitcontrolling devices in each of such connections.

20. The combination with two electric motors, of two resistances,contacts connected directly to said motors, contacts connected to saidmotors through resistances, a cross arm bridging the resistance contactsor the direct contacts alternately and movable terminals connected tothe outer terminals, of the motors and engaging with said contacts.

21. The combination with a constant potential circuit, of two motorshaving outer connections to opposite sides thereof, and innerconnections to separate contacts, two sets of resistances respectivelyconnected to said innor connections and to separate contacts, a crossarm bridging said motor contacts or said resistance contactsalternately, and movable terminals connected to the outer connections ofthe respective motors, and making contact with the resistance contactsof the opposite motors while the cross arm is still in connec tion withthe motor.

22. The combination with a constant potential circuit, two electricmotors connected respectively thereto, a separable connection betweensuch motors, and separable connections around each motor, eachcontaining a resistance sufficient to prevent short-circuitln g ofeither the motors or the supply circuit.

23. The combination with a constant potential circuit, of two electricmotors, separable connections connecting said motors in series in saidcircuit, and separable shunting connections around each motor andcontaining resistances, the total resistance of the path through suchshunt connections having about the same ratio to the total resistance ofthe path through the motors, that the electromotive force of the linehas to the efiective elec- 45 trornotive force through said motor path.

In testimony whereof I have hereunto set my hand this 21st day ofJanuary, 1892.

ARTHUR P. KNIGHT. Witnesses:

N. F. HAYES, H. J. LIVERMORE.

